Blood vessels are crucial for organ growth in the embryo and repair of wounded tissue in the adult. An imbalance in the growth of blood vessels contributes to the pathogenesis of numerous disorders including malignant, ocular and inflammatory disorders. Carmeliet, Nature 438: 932-936 (2005). Excessive or abnormal angiogenesis may contribute to conditions such as obesity, asthma, diabetes, cirrhosis, multiple sclerosis, endometriosis, AIDS, bacterial infections and autoimmune disease. Id. Insufficient angiogenesis may cause endothelial cell dysfunction and vessel malformation or regression; it may also prevent revascularization, healing and regeneration thereby contributing to ischaemic heart disease or preeclampsia. Id. To date, it has been reported that in Western nations, at least 184 million patients could benefit from some form of anti-angiogenesis therapy, while at least 314 million patients would benefit from some form of angiogenesis-stimulating therapy (http://www.angio.org/understanding/content_understanding.html (last retrieved May 16, 2006)).
Although a great deal of effort has been undertaken to develop therapies to promote revascularization of ischemic tissue or to inhibit angiogenesis in cancer and ocular, joint or skin disorders, toxicities and acquired resistance associated with currently available therapeutics indicate that continued efforts to develop novel strategies for treating angiogenesis-associated conditions are needed.